<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>css2 模拟圆角</title>
</head>
<body>
    <style>
        .button {
            display: inline-block;
            height: 30px;
            line-height: 30px;
            width: 150px;
            color: #fff;
            text-align: center;
            background-color: red;
            position: relative;
        }
        .button::before, .button::after{
            position: absolute;
            left: 0;
            right: 0;
            border-style: solid;
            content: "";
        }

        .button::before {
            top:-2px;
            border-width: 0 2px 2px;
            border-color : transparent transparent red ;
        }

        .button::after{
            bottom: -2px;
            border-width: 2px 2px 0px;
            border-color: red transparent transparent;
        }
    </style>
    <a class="button">我是一个按钮</a>
</body>
</html>